The answer depends on whether you ask a scientist or a chef. From the scientific point of view, a fruit is the ripened reproductive organ of a plant. By that definition, fruits always contain seeds, at least in the natural world. Horticulturalists have developed "seedless" versions of some fruits, such as seedless grapes and seedless watermelons; in these particular fruits, the plant has been bred so that the seeds develop much more slowly than the fruit does. When the fruit is ripe, there are in fact seeds present, but they are very small and soft, and usually are not very noticeable. Vegetables, according to the science definition, are non-reproductive plant parts such as roots, stems, and leaves.
Chefs define fruits and vegetable according to how they are used in cooking. In most culinary traditions, vegetables are considered to be non-sweet plant parts that are usually eaten as part of an appetizer or as part of the main meal. Fruits are usually sweet, and are used as desserts and treats.
A fruit is the swollen ovary of a plant whereas a vegetable is usually the root, leaf or stem of a plant. :)
Vegetable normally refers to the edible leafy green, stem, root or even flower stalk portion of a plant.
Examples of vegetables include: carrot, potato, lettuce, cabbage, onion, cauliflower,etc.
A fruit is an edible ripened ovary of a plant, enclosing the seeds which are the mature ovules.
Examples of fruit include:peach, pear, cherry, orange, apple, banana, mellon,etc.